I don't really care if Bezos buys the Celtics. At the cost of a sports franchise these days, pretty much every one is going to be owned by someone like him in time anyway. The stadium aspect of this is getting a lot of talk, with the thinking being that Bezos would build a stadium for the Celtics. I don't think Boston needs a stadium for Hockey and a stadium for Basketball. That doesn't make sense to me. I suppose Bezos could buy the Garden from Jacobs.
Financially, it seems that investing in a sports franchise would be a good diversification for him. It would only take a few of his 100s of billions to buy it. I am not sure he has the personal bandwidth to get too involved in the business of the Celtics. It would probably be better than Henry buying the Celtics.